This project has made significant advances both in technology enhancements for single virus particle reconstruction as well as insights into the structure of herpes simplex virus capsid during its maturation. Our goal is to improve the resolution of the structural determination of large spherical viruses beyond 10 [unreadable]. We have determined the HSV B capsid structure to ~9.5 [unreadable] and are still improving the quality of the map. In addition, we have studied various recombinant particles made from different types of capsid structural proteins. This has led us to identify the locations of contact points between the inner surface of the capsid coat proteins and the scaffolding proteins.